Electric weft detector



Dec. 2, 1941. Vo. v. PAYNE 2,264,771

ELECTRIC wEFT DETECTOR Filed April 211941I 1. KWQQM n 34 .To www unmwnuh Y/ 34j/ s?, 34)L A\ 34 5s 3 A FIG E FIG.) 4

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OSCARV-PAYNE LM?- FIE.7 -v-YORNEY Patented Dec. 2, 1941 ELECTRIC. WEFT DETECTGBL' Oscar V.. Payne, Leicester,l Mass., assgnor to, Crompton & Knowles Loom. Works, Worcester, Mass., a., corporation or Massachusetts Application April; 2l, 1941 Serial No.389,595

10, Claims.

This invention relates to improvements in electrical weft detectors and it isA the general objecty of the invention to` provide the detector with a bobbin contacting tip which exert low pressure on the weft being detected to prevent abrasion thereof.

It has been customary heretofore in electrical weft detectors to employ slidable wiresy t-he rear ends of which` engage the weft. In such detectors the pressure on the weft is relativelyv high due to the fact thatthe area of contactV is small. It is an` important object of my present invention to provide a weft detector having elongated contact tips which extend' along the length ofth'e bobbin to distribute the force of impact and thereby reduce the pressure.

It is a further object of my present invention to provide a pair of tips which are formed of wires having their rear ends built laterally and so shaped that the part of the bent end which rst strikes the weft is located laterally a considerable distance from that part of the wire which is held to its support. In this way the tip offers very low mechanical resistance to the advance of the weft in the initial stages of' th'e detecting operation.

It is another object of my invention to provide thetips with means for holding them detachably on a carrier by means readily accessible from the outsideof the detector. Weit detectors as heretofore constructed' have had their electrical elements encased in such a way as to require partial disassembly before the detector tips could be removed. It is another feature of my invention to provide a U-shaped tip one arm of which is sufciently long to be secured directly toa sliding carrier and the other arm of which moves freely in a forwardly extending bore in the rear end of the carrier. By this construction both arm-.s of the tip are h'eld in proper position for detecting but can be readily removed without disturbing the slide or any part of it other than the tip being replaced.

It is still another object of my present invention to provide a weft detector with a carrier slide formed with elongated slots in which are located light compression springs which tend to hold the slide and its feeler tips normally in rear position. The coil springs are part of the detector circuit and have electric contact at their rear ends with the detachable connections for the feeler tips and at their forward ends with contact screws on the carrier support which enter the slots to limit rearward motion of the carrier.

With these and other objects in view which will appear as the description proceeds, my inv vention resides in the combination and arrangement of parts hereinafter described and set forth.

In the accompanying drawing.V whereiua. convenient embodiment of my inventionis set forth,

Fig; I is a plan view partly in section. of a weft detector made according to my presentinvention and showing the same as related to a bobbin. being detected,

Fig. 2 is a vertical. longitudinal section Online 2.-2 ofV Fig. 1 showing the slide inl forward position relatively toits support.

Fig. 3; is a front elevation of the detector lookingv in th'e direction of arrow 3, Fig. 1,

Fig. 4 is an enlarged vertical section, on line 4 4 of Fig. 1,

Fig. 5.is.a fragmentary side elevation of a portion of the slide indicating the manner in which the detector tip is secured to. it,

Fig. 6; is an enlarged rear' elevation looking in the direction of arrow: 6,` Fig. 2,l and Fig. 'l is a detail' of one of the contact, tip wires.

In Fig. 1 I have shown a lay L carryingy a shuttle S in which is located a bobbin B wound with a mass of weft W. The b arrel of the bobbin is provided withx a metallic. ferrule l0 which is, ordinarily covered by the weft but which is uncovered as weft exhaustion approaches. The lay' moves forwardly to present the. bobbin to the detector D and the latter will ordinarily have contact witl'l` the bobbin on alternate beats of the loom. A support' Il held tothe loom frame not shown is for the purpose ofA supporting the detector.

In carrying my present invention into effect I provide a casing (Jv having a cover l2 and base lf3 the front ends ofwhich are relatively wide as at I4 to receive spaced bolts l5 which extend through the casing and hold the latter to the support ll by nutsA I6. The base I3: is held to the upper part of th'e casing by screws Il So that the top and the bottom of the casing may be separated.

The cover has a slot i8 therein the bottom of which is closed by the base I3 to dene an enclosed guideway for a carrier or slide 20 which has formed in the upper surface thereof a pair of elongated narrow grooves or open slots 2l in each' of which is located a compression spring 22. The forward end of each spring bears against a depending contact screw 23 threaded through the top of the casing and having contact, with a plate 241 which leads to a. binding post 25. As shown in 3 the binding posts are connected to wires 26 leading to an external circuit not shown which' effects a change in loom operation when the contact screws 23 are electrically connected.- The screws 2-3 also project downwardly into the slots 20 and engage the frontend of the carrier to limit rearward motion thereof under action of the springs 212.

The carrier or slide 20 is formed of insulating material and is provided with a broadened head 33 having shoulders 3l positioned for engagement with the rear surfaces 32 of the cover l2 of the case C to limit forward motion of the carrier. In the rear end of each slot 2l is a block of metal 33 into which is threaded a screw 34 projecting inwardly from an outer surface of the head 30 and helping to hold the block in the slot. The rear end of each spring 22 bears against one of the blocks 33 and in this way-the latter are electrically connected to their corresponding contact screws 23.

The feeler tips are in the form of thin resilient wires indicated generally at 35. Each wire is U- shaped and has a forwardly extending arm 36 held under the head of one of the contact screws 34. Each long arm 36 extends rearwardly along the adjacent edge of the carrier slide and through a slot 43 formed in the carrier to project beyond the rear end of the latter. Each wire is then bent as at 4| to form a contacting section 42 extendinnr laterally and rearwardly to a second bend 43 which is normally to the rear of bend 4|. From bend 43 the wire extends forwardly to form a slot arm 44 received by a small horizontal forwardly extending bore 45 in the carrier 23.

By referring to Fig. 6 it will be seen that the contact sections 42 of the two tips are vertically spaced and are out of electrical contact with each other,` and extend in the direction of the length of the bobbin to be detected. Each bend 43 is displaced laterally a considerable distance from its corresponding -long arm 36 and therefore yields under a light pressure when struck by the bobbin.

In operation, the springs 22 will hold the carrier normally in rear position and the curved parts 43 will be disposed substantially as shown in Fig. l with the sections 42 of the tip slightly inclined rearwardly from their respective arms 36. As the bobbin advances the surface to be detected will engage the bent portions 43 and move the same forwardly relatively to the carrier 2B, the short arms 44 moving longitudinally and forwardly within their bores 45. So long as sufficient weft for continued Weaving is present the wire tips will be out of electrical contact with each other, but when the ferrule III is uncovered the two tips Vare electrically connected and as will be understood from the description already given, the wires 26 will be electrically connected to effect the necessary change in loom operation. The loom controlling circuit will include bends 43 and long arms 33, screws 34, blocks 33 and the springs 22, and also the contact screws 23, plates 24 and binding posts 25.

Forward motion of the slide 20 will be resisted by its inertia and also the rearwardly directed force of the springs 22. This force will ordinarily be great enough to cause the bending of one of the contact wires so that if either of the latter should become bent rearwardly beyond its normal position it will be bent forwardly until the ferrule engages the other wire. After engagem'ent, the wires will bend until the sections 42 contact the ferrule to insure a long line or area 'ofcontact for the flow of electric current. During the detecting operation the sections 42 become temporarily parallel.

Should either of the wire tips require repair it caribe removed by loosening the associated contact screw 34 and moving the tip wire rearwardly.

When restored to proper form or replaced, short arm 44 is inserted into its bore and the long end 36 then caught under the head of the previously loosened contact screw 34. One bore 45 is under a slot 40 and one side of the carrier, while the other bore is over its corresponding slot 4i) at the other side.

From the foregoing it will be seen that I have provided a simple form of electric weft detector wherein the contacting tips extend along a con siderable length of the surface to be detected, thereby distributing the pressure exerted by the tips on the weft and reducing abrasion of the latter. It will also be seen that the Wire tips are so formed that they engage the bobbin at a point laterally offset from the long arms 3B and can therefore bend under light pressure. Furthermore, the .resistance to bending offered by the tips is so related to the force required to move the carrier forwardly that one tip will be bent upon engagement with the ferrule ID until the latter can engage the other tip, after which the slide 20 will move forwardly. Furthermore, the electric circuit is completed through the blocks 33 and the springs 23 and the Vcontact screw 23 not only serve the purpose of conducting electric current-but also limit rearward motion of the slide carrier 2D. Also, a damaged contact tip may readily be removed and replaced by manipulation of the corresponding contact screw 34.

Having thus described my invention it will be seen that changes and modifications may be made therein by those skilled in the art without departing from the spirit and scope of the invention and I do not wish to be limited to the details herein disclosed, but what I claim is:

1. In an electric weft detector for looms, a stationary support, a carrier slidable on the support, electric contact elements on the support to engage the carrier and limit rearward motion thereof, compression springs insulated electrically from each other and each engaging one of the contact elements, the springs acting on the carrier to hold the same yieldingly in rear position. and resilient electric contact tips carried by and projecting rearwardly from the carrier and insulated from each other and electrically connected one to each of said compression springs, the resistance to forward flexing offered by one of said tips when engaging a bobbin being less than the resistance offered by said springs and the force of inertia of the carrier to forward movement of the latter.

2. In an electric weft detector for looms, a stationary support, a carrier slidable on the support, electric contact elements on the support to engage the carrier and limit rearward motion thereof, compression springs insulated electrically from each other and supported by the carrier and each engaging one of the contact elements and holding the carrier yieldingly in rear position relatively to the support, and resilient electric Vcontact tips carried by and projecting behind the carrier and insulated from each other and electrically connected one to each of said com'- pression springs, the resistance to forward flexing offered by one of said tips when engaging a bobbin being less than the resistance offered by said springs and the force of inertia of the carrier to forward movement of the latter, and the resistance to flexing of both of said tips being greater than the resistance to forward motion of the carrier offered by said compression springs and the inertia of said carrier.

3. In an electric weft detector for looms, a fixed support formed of electric insulating material, a carrier movable backwardly and forwardly on the support, compression springs insulated from each other and acting on the carrier to move the latter rearwardly relatively to the support, two contact elements on the support one in engagement with each spring, means to limit rearward motion of the slide relatively to the support, and a pair of electric contact tips mounted on the carrier and projecting rearwardly therefrom and insulated from each other, each tip being electrically connected to one of the contact springs and each tip comprising an inherently resilient member extending from one side of the carrier in a direction transversely of the latter and rearwardly for engagement with the uncovered metallic ferrule on the bobbin being detected, each detector tip being yieldable forwardly relatively to the carrier by a force less than that required to move the carrier forwardly.

4, In an electric weft detector for looms, a fixed support formed of electrically insulating material, a carrier formed of electrically insulating material movable backwardly and forwardly on the support, a pair of electric contact tips on the carrier insulated from each other, a pair of contact elements on the support each connected to one of the tips, each contact tip comprising an inherently resilient wire supported on the carrier at one side thereof, one tip for each side of the carrier, and each tip extending rearwardly beyond the rear end of the carrier and then transversely of the latter and diagonally rearwardly toward the opposite side of the carrier to present an area of initial engagement with the surface being detected, and yielding means to hold the carrier rearwardly with respect to the support, each detector tip having the area of initial contact thereof yieldable forwardly by a force less than that required to move the carrier forwardly.

5. In an electric weft detector for looms, a fixed support, a carrier movable backwardly and forwardly on the support, means to hold the carrier yieldingly in rear position on the support, a pair of substantially U-shaped electric contact elements made of resilient electric conducting wire insulated electrically from each other and each having a pair of substantially parallel arms,

means to secure one arm of each element, each to its individual side of the carrier, one arm secured to each side of the carrier, the carrier having guide recesses for the other arms of the elements, that portion of each detector element positioned for engagement with the surface to be detected extending from one arm thereof in a direction transversely of the carrier and rearwardly to the other arm thereof, eachV detector element having that part thereof adapted for engagement with the surface to be detected yielding to a forward force less than that required to move the carrier forwardly.

6. In an electric weft detector, a fixed support formed of insulating material, a slide mounted on the support also formed of insulating material, a pair of spaced parallel grooves in the slide, a block of electric conducting material located in the rear end of each groove, electric contacts on the support each extending into one of the grooves to limit rearward movement of the slide relatively to the support, a metallic compression spring in each groove engaging one of the contacts and one of the blocks, electric contact tips mounted on the slide and positioned for engagement with a metallic surface behind the Slide, and an electric conducting element engaging each contact and holding the latter to the slide and having contact with the corresponding block,

said compression springs holding the slide yieldingly rearwardly relatively to the support.

7. A contact tip for an electric weft detector comprising a carrier formed of electric insulating material and a pair of electric current conducting inherently resilient U-shaped contact tip members each having a pair of substantially parallel arms connected together by a transverse contact section, one arm of one tip member being secured to one side of the carrier and one arm of the other tip member being secured to the other side of the carrier, the other arms of the tip members being guided by the carrier for forward motion relatively thereto, each -contact section extending transversely of the carrier and rearwardly with respect thereto in a direction from the arm thereof secured to the carrier to the arm thereof which is guided by the carrier, said tip members presenting two contact areas transversely spaced relatively to the carrier and each yieldable forwardly.

8. A contact tip for an electric weft detector comprising a carrier formed of electric insulating material and a pair of electric current conducting inherently resilient U-shaped contact tip members each having a pair of substantially parallel arms connected together by a transverse contact section, one arm of one tip member being secured to one side of the carrier and one arm of the other tip member being secured to the other side of the carrier, the other arms of the tip members being guided by the carrier for forward motion relatively thereto, each of said contact sections being oblique relatively to the surface to be detected with a contact area thereof remote from the corresponding arm which is secured to the carrier and to the rear of said corresponding arm, each contact area movable forwardly relatively to the carrier when engaged by the surface to be detected to cause the corresponding Contact section to extend along and in contact with the surface being detected.

9. In an electric weft detector for a loom operating with an elongated surface to be detected, a supporting carrier extending forwardly from the surface to be detected, a pair of resilient contact members supported by the carrier and insulated from each other and extending in opposite directions from opposite sides of the carrier and each having a portion extending transversely of the carrier between the latter and the surface to be detected and obliquely with respect to the latter toward the surface to be detected, the rearmost portion of each member being bendable forwardly by the surface being detected to cause the members to extend along and in contact with the surface being detected.

10. In an electric weft detector for a loom operating with an elongated electric conducting surface to be uncovered as weft exhaustion approaches, a supporting member extending forwardly from said surface, a pair of vertically spaced contact tips secured to the member and insulated from each other and formed of inherently resilient electric conducting material and extending obliquely and in opposite directions toward the surface to be detected, each tip having one portion thereof nearer` the surface than other portions thereof and the first named portion being yieldable forwardly relatively to the member when engaged by said surface to permit said other portions to engage the surface OSCAR V. PAYNE. 

